Benzoxazines and compositions containing benzoxazine are known (see for example, U.S. Pat. Nos. 5,543,516 and 6,207,786 to Ishida, et al.; S. Rimdusit and H. Ishida, “Development of New Class of Electronic Packaging Materials Based on Ternary Systems of Benzoxazine, Epoxy, and Phenolic Resins”, Polymer, 41, 7941-49 (2000); and H. Kimura, et al., “New Thermosetting Resin from Bisphenol A-based Benzoxazine and Bisoxazoline”, J. App. Polym. Sci., 72, 1551-58 (1999).
U.S. Pat. No. 4,501,864 (Higginbottom) reports a curable composition comprising a poly(3,4-dihydro-3-substituted-1,3 benzoxazine) and a reactive polyamine, wherein the polyamine is at least difunctional and its reactive groups are primary or secondary amine, and wherein the poly(dihydrobenzoxazine) is the reaction product of about one equivalent of a primary amine, about one equivalent of a phenol and about two equivalents of formaldehyde.
PCT Published Patent Application WO 2010/141396 A1 (Gorodisher et al.) describes benzoxazine-thiol adducts which may be cured to produce compositions useful in coatings, sealants, adhesives, and other applications. Similarly, PCT Published Patent Application WO 2009/115586 A1 (Burns et al.) describes adducts useful for improving the toughness and curable compositions using such toughening adducts.